Observation of the decay B[superscript 0][subscript 2]→ϕπ[superscript +]π[superscript -] and evidence for B[superscript 0]→ϕπ[superscript +]π[superscript -]

The first observation of the rare decay B[superscript 0][subscript s]→ϕπ[superscript +]π[superscript -] and evidence for B[superscript 0]→ϕπ[superscript +]π[superscript -] are reported, using pp collision data recorded by the LHCb detector at center-of-mass energies √s =7 and 8 TeV, corresponding to an integrated luminosity of 3 fb[superscript -1]. The branching fractions in the π[superscript +]π[superscript -] invariant mass range 400<m(π[superscript +]π[superscript -])<1600 MeV/c[superscript 2] are [3.48±0.23±0.17±0.35]×10[superscript -6] and [1.82±0.25±0.41±0.14]×10[superscript -7] for B[superscript 0][subscript s]→ϕπ[superscript +]π[superscript -] and B[superscript 0]→ϕπ[superscript +]π[superscript -] respectively, where the uncertainties are statistical, systematic and from the normalization mode B[superscript 0][subscript s]→ϕϕ. A combined analysis of the π[superscript +]π[superscript -] mass spectrum and the decay angles of the final-state particles identifies the exclusive decays B[superscript 0][subscript s]→ϕf[subscript 0](980), B[superscript 0][subscript s]→ϕf[subscript 2](1270), and B[superscript 0][subscript s]→ϕρ[subscript 0] with branching fractions of [1.12±0.16[superscript +0.09][subscript -0.08]±0.11]×10[superscript -6], [0.61±0.13[superscript +0.12][superscript {-0.05]±0.06]×10[superscript -6] and [2.7±0.7±0.2±0.2]×10[superscript -7], respectively.